I have a 55 gallon marine aquarium. It has been cycling for almost 6 weeks,four weeks with a damsel. The rocks are not live, however there is green algae growing good on them and some brown also growing. I am eventually going to start a reef /fish system.The question I have is: I have crushed(med. and large) coral as a substrate. Can I use sand on one end of the tank,1/4, and CC on the other 3/4 of tank? And where if i can, put the sand? By live rock or away from rock/reef ?